Range and elevation determining device

ABSTRACT

A range and elevation determining device serving in one form as a sight for direct fire gunnery. May be in the form of a stadimetric ranging and sight setting device that when adjusted by the gunner to frame a target automatically will dictate proper elevation of the gun muzzle to accommodate known trajectory and range characteristics of certain ammunition and will direct, upon firing the gun, the projectile thereof to a selected kill point on the target. A front sight is provided as a rotatable disk that is pivotally mounted on an upright support on the gun muzzle. It may be a &#39;&#39;&#39;&#39;see-through&#39;&#39;&#39;&#39; or transparent disk. This disk is provided about its axis with a spiraled framing area having curved marginal framing stadia or lines that gradually converge in the direction of disk rotation from point blank or near range toward the longest effective range of the gun on which it is mounted and the ammunition used therein. Framing of the height of the image of a distant target between these marginal stadia automatically will indicate range whether or not such data is readably provided on the device. Preferably the disk is provided with annularly spaced radial lines that are respectively identified by readable range markings. The spiraled framing area may be a slot in the disk. The disk may be a reticule that is rotatably mounted in image planes of optical instruments, such as binoculars, gunner&#39;&#39;s telescopes and periscopes, and provided with suitable readable markings that inform one accurately of the range and elevation data.

United States Patent Smith et a1.

[ Sept. 5, 1972 [54] RANGE AND ELEVATION DETERMINING DEVICE [72]Inventors: James P. Smith, 71 Vanderwater Ave., Floral Park, NY. 11001;Erwin Michelson, 1.02 Eighteenth Ave., East Paterson, NJ. 07407 [22]Filed: Feb. 19, 1971 [21] Appl. No.: 116,843

52 US. Cl ..33/64 B, 33/1 SP, 33/54 51 Int. Cl. ..G0lc 3/00 [58] Fieldof Search ...33/64 B, 64 R, 64 c, 71, 49 R,

33/49 c, 1 SP, 54

I56] References Cited UNITED STATES PATENTS 444,406 1/1891 Andrews et al..33/64 B X 1,466,913 9/ 1923 Matthews ..33/54 3,365,800 1/1968 Carella..33/64 R X FOREIGN PATENTS OR APPLICATIONS 630,706 12/1961 Italy..33/64 B 79,570 2/1934 Sweden ..33/64 B 105,637 10/1942 Sweden ..33/ 1SP Primary Examiner-Robert B. Hull Att0meyl-larry M. Saragovitz, EdwardJ. Kelly and Herbert Berl [57] ABSTRACT A range and elevationdetermining device serving in one form as a sight for direct firegunnery. May be in the form of a stadimetric ranging and sight settingdevice that when adjusted by the gunner to frame a target automaticallywill dictate proper elevation of the gun muzzle to accommodate knowntrajectory and range characteristics of certain ammunition and willdirect, upon firing the gun, the projectile thereof to a selected killpoint on the target. A front sight is provided as a rotatable disk thatis pivotally mounted on an upright support on the gun muzzle. It may bea see-through or transparent disk. This disk is provided about its axiswith a spiraled framing area having curved marginal framing stadia orlines that gradually converge in the direction of disk rotation frompoint blank or near range toward the longest effective range of the gunon which it is mounted and the ammunition used therein. Framing of theheight of the image of a distant target between these marginal stadiaautomatically will indicate range whether or not such data is readablyprovided on the device. Preferably the disk is provided with annularlyspaced radial lithes that are respectively identified by readable rangemarkings. The spiraled framing area may be a slot in the disk. The diskmay be a reticule that is rotatably mounted in image planes of opticalinstruments, such as binoculars, gunners telescopes and periscopes, andprovided with suitable readable markings that inform one accurately ofthe range and elevation data.

8 Claims, 7 Drawing Ih'gures PATENTED 5|973 I 3.688.408

- sum 1 OF 2 8 8 N N mm i 9 INVENTORS, JAMES E SMITH, BY; ERWINMICHELSON W M ,qrroRNEY PATENTEDSEP 51912 SHEET 2 BF 2 INVENTORS JAMESPSMITH BY- ERWIN MICHELSON A M W1 1 RANGE AND ELEVATION DETERMININGDEVICE BACKGROUND OF THE INVENTION The present invention relates torange and elevation determining devices that are particularly useful ingun nery, such as of the direct fire category, e.g., shoulder firedweapons of the LAW (light anti-tank weapon) type. For this purpose itmay be embodied in the front sight assembly of the weapon.

Prior to the present invention it has been proposed that the sightingequipment of such a weapon embody means which will present to the gunnerin the line of sight an image of the distant target. The size of theimage of the distant target object bears a certain geometrical relation-to the range or distance between the point of observation and theobject, i.e., the angle subtended by any particular dimension of thedistant object depends upon this dimension and such distance. Some typesof such guns have no range finding or stadimetric devices as such, andrequire range estimation by the gunners usually under very difficultconditions. Others provide in the front sight assembly vertical stadialines to facilitate range estimation with calibration thereof related totarget object side-on or head-on view. In the latter cases when thetarget object is viewed from any other angle range estimation errorsreadily are made since the observer must estimate such angle.

It has also been proposed in the Walker et al. British Pat. No. 1204 ofJan. 26, l888 that a small weapon or shoulder-fired rifle be equippedwith complicated sighting equipment that employs a sophisticatedtelescope as a rear sight. Use of this telescopic rear sight employs aknowledge of the average height of a recognizable target object fordetermining range and translating this value into the action of theequipment for attaining a hit with some accuracy. It also permitsembodiment thereof in range finding devices, such as telescopes andbinoculars. In any case it requires installation in such objectivesystem of two vertically movable masking plates having opposed,horizontal and parallel edges between which a lateral viewing slot isdefined, with these plates being simultaneously movable relative to eachother in their plane of alignment for varying the width of the viewingslot with the opposed slot-defining edges continuously located at equaldistances below and above the axis of the lens system.

In the rifle supported form of the Walker et al. device the telescope ismounted upon a parallel linkage so that it may be raised and lowered byhand while keeping its objective axis aligned with the front sight todefine a line of sight to the distant target. The telescope tubeslidably carries a surrounding sleeve. Internally of the tube thissleeve carries by vertically aligned compound screw and slidable pin astirrup collar through which an opposed pair of vertically spaced,longitudinally extending spring leaves extend. Forward ends of thesespring leaves are fixed to top and bottom portions of the tube withtheir rear ends bent inwardly toward each other to form the opposed andslot-defining masking plates. The stirrup supporting screw and pinextend out through longitudinal slots in the top and bottom portions ofthe tube, to permit longitudinal adjustment of this sleeve andstirrupassembly along the telescope tube, with bell cranks on some leverarms of the parallel linkage sliding this assembly along the tube axisby connecting links as the telescope is raised and lowered. Thislongitudinal adjustment of the stirrup imposes a camming action upon thespring leaves to cause the opposed horizontaledges of the masking platesto approach each other and, alternatively, to separate for adjustableframing of the image of the distant target.

One of these bell crank carrying arms has its mounting axle equippedwith a pointer which swings along. a graduated scale or quadrant so asto indicate the range as the opposed plate edges frame the bottom and toof the image of the distant target.

In the binocular embodiment of the Walker'et al. device each of the pairof sight tubes is equipped with the opposed pair spring leaves and theirencompassing stirrup. The compound screw of this assembly, which in thisform is at a fixed point on the sight tube translates the stirruptransversely or across the tube optical axis to move one of the springleaves therewith while the inner end of the screw bears against theopposed spring leaf to move it relative to the first in the oppositedirection. Gearing is employed to gang these compound screws togetherand one or more of the gears carries a graduated range scale.

proposals are solved in a simple and economical manner by the presentinvention.

SUMMARY Various embodiments of the present range and elevationdetermining device, which may serve as a front sight for direct firegunnery or as a reticule in op tical field instruments, e.g.,binoculars, gunners telescopes and periscopes, to provide accurate rangedata, employ a simple rotatable disk and support therefor. This disk isprovided with a spiraled seethrough framing area defined between curvedmarginal framing stadia that gradually converge in the intendeddirection of disk rotation for closely framing visually therebetween theimage height of a distant object. This framing area at its greatestwidth is located most closely to the axis of rotation of the disk andspirals gradually outward toward the periphery of the latter as itsmarginal stadia progressively converge. As a result, when the height ofthe object image is closely framed between these marginal stadia bysuitable rotary adjustment of the disk the angular or radial location ofthis framed image in the disk framing area indicates the range betweenthe location of the object and the point of observation while the radialdistance from the axis of the disk to a selected or intended hit portionof or point of impact on the framed image indicates the angularelevationnecessary to accommodate the characteristic trajectory of acertain projectile. In a preferred embodiment radii of the disk aredelineated thereon as representative of certain range distances forindicating at least some of the radial locations at which such ob jectimage framing is to be effected and, if desired, the disk face may hearan annular graduation of radials to enhance its use as a range finder.

The spiraled framing area of this disk may be in the form of a spiraledslot with the curved edges thereof constituting its marginal stadia. Insuch form the disk may be constructed of opaque sheet material. In apreferred form the disk is constructed of see-through transparentplastic sheeting with the spiraled framing area defined thereon byembossed or scribed curved lines to constitute the marginal framingstadia. This preferred form of the disk permits the scribing thereon,between the marginal framing stadia of a curved medial line that extendsthrough points at the range distances radii which will indicate a theserange distances the desired points of impact for the intended target.This medial line defines the hit point at each of all of the rangedistances between the initial and terminal points of this spiraledframing area and with the radial distance between this hit point lineand the axis of the disk indicating the required angular elevation ofthe weapon tube relative to the line of sight.

When this range and elevation determining rotary disk is employed as afront weapon sight its exposed circumferential rim may serve for readyengagement by the gunners hand for simple rotation thereof about itsaxis to obtain the desired adjustment for the close framing of thetarget image height in the curved framing area.

When such a rotary range and elevation determining disk is laid out andproduced for use as the front sight of a particular weapon, in relationto the distance between this front sight and the rear sight and withrespect to characteristics of certain particular ammunition to be usedin this weapon for accurate accommodation of the trajectory andeffective range thereof, duplicates thereof for simple mounting upon thenumerous reproductions of the weapon may be economically and rapidlyproduced by simple die-cutting, and stamping procedures. The mountingthereof can also be effected in a simple and rapid manner.

BRIEF DESCRIPTION OF THE DRAWINGS Other objects of the invention will inpart be obvious and will in part appear from reference to the followingdetailed description taken in connection with the accompanying drawings,wherein certain relative dimensions have been exaggerated for clarity ofunderstanding, with the understanding that dimensions of exemplary gunparts are so small relative to range distances that in showingsinvolving both the former virtually disappear or may be ignored to avoidconfusion in such small scale depictions. In these drawings like indiciaand numerals identify similar parts throughout, wherein:

FIG. 1 is a perspective view of a light anti-tank weapon LAW-bazooka) inwhich a form of the present range and elevation determining device maybe embodied to advantage as a front sight, the telescopic gun tubethereof being shown in extended condition with the rear and front sightsbeing swung up to operative upright positions;

FIG. 2 is a rear elevational view, to enlarged scale, of the rear sightof the weapon depicted in FIG. 1, with the protective hood thereofremoved;

FIG. 3 is a rear elevational view, to enlarged scale, of the front sightof the weapon depicted in FIG. 1;

FIG. 4 is a rear elevational view, to larger scale, of a front sightassembly which may be advantageously substituted for that of FIG. 3;

FIG. 5 is a diagrammatic layout to greatly reduced scale of thecombination of rear and front sights of FIGS. 2 and 4 when mounted uponthe weapon of FIG. 1, illustrating geometric relationships of range andtrajectory for certain ammunition to be fired through the gun tubeofFIG.1;

FIG. 6 is an enlarged diagrammatic view of the FIG. 1 weapon whenequipped with the rear sight of FIG. 2 and the front sight of FIG. 4,that illustrates the necessary angular elevation of the gun tube forattaining a hit at a certain intermediate range; and

FIG. 7 is a diagrammatic view similar to FIG. 6 illustrating a greaterangular elevation required to attain a hit at a greater range which maybe in the vicinity of the greatest reliable range of which this weaponis capable.

The weapon 10 of FIG. 1, which is illustrated by way of example as anLAW that may be improved to advantage by the present invention, includesa gun tube 11 formed of telescopic rear and front sections 12 and 13which are shown in their relative extended positions, readied forreceiving ammunition therein and firing projectiles therefrom. The guntube 11 conventionally includes triggering mechanism 14 operated by alanyard 15 from a trigger 16, with the latter carried in a medialposition by a support 17 upon which is pivotally mounted the rear sight(RS). The rear sight (RS) is shown swung up to its upright position foruse. The front end or muzzle 18 pivotally supports by a bracket 19 thefront sight (FS) which has also been swung up to its upright position ofuse.

As will be understood from FIG. 2 the fulcrumed rear sight (RS) includesa pivotally supported bracket 20. This bracket 20 conventionally has atemperature adjusting slide 21 equipped with a cold temperature sightpeephole RSC) and a normal temperature peephole( RSN).

As will be understood from FIG. 3 the fulcrumed front sight (FS)includes a see-through or transparent plastic card 22 which is embossedor scribed with a vertical center line 23 across which extend verticallyspaced, transverse stadia 24, with some of the latter identified byembossed or scribed range meter indicia or markings. The vertical centerline 23 is flanked on opposite sides by opposed, upwardly extending,curved stadia 25 and between which a target image may be framed forestimating the range distance of the target from the weapon or, moreparticularly, the rear peep sight (RS). In FIG. 3 is illustrated at 26 aframing between the stadia lines 25 and 125 of a side-on view of theobjective image of a tank, and such framing provides the gunner withinformation to aid him in estimating the range distance to the tankwhich is afforded by the basic stadirnetric principle that the anglesubtended by an object depends on its length or width and its distancefrom the observer. Such a front sight (FS), which includes the uprightcard 22, may be employed also for framing a head-on view of the tank byknown technique, but such front sight equipment readily permits rangeerror to be made by the observer or gunner when the target tank isviewed from any other angle, since such angle must be estimated. Thefront sight card 22 also conventionally flanks opposite sides of thevertical center line 23 with lead markings (shown as plus signs whichmay also be employed in the improved front sight of the presentinvention.

For the purpose of understanding the FIG. 4 embodiment of the presentinvention as a front sight of such a FIG. 1 gun, which will be describedhereinafter in detail, it should be recalled that intelligence andexperience has provided the information that most enemy tanks now areabout feet (10') from the ground to the top of the turret, andintelligence information will have apprised the gunners of recognizablecharacteristics of such tanks so that they will instantly associate theobserved type with such a characteristic height. For the purpose of thefollowing exemplary description of the present invention it will beassumed that such target tank will have a height of about 10 feet (120inch or 3.048 m). By using the target height rather than the targetlength or width the source of prior range estimation error is eliminatedautomatically.

In the front sight FIG. 4 embodiment the plastic card 22 has substitutedtherefor an upright support strip 30, which may be of see-through ortransparent plastic or, if of opaque material, such as sheet metal, maybe provided with a suitable window 31 below a pivot point or axis 32. Atthe axis point 32 a suitable pivot pin, which may be a rivet or othersimple type of fastener axle, rotatably supports a see-through ortransparent plastic disk 33, which is preferably of relatively stiffsheeting, mm be rotated by hand, and equipped, if desired, with aknurled circumferential edge, such as that which is indicated at 34, andit is to be understood that other suitable means, such as simplemechanism which will readily occur to one skilled in the art, may beprovided for effecting such rotation of this disk. The disk 33 isscribed with a plurality of equally-spaced radials, such as (RR-l,-RR-2,RR-3,,RR4, and RR-S which may delineate ranges in meters of 100m, 200m,300m, 400m, 500m. Such radials may be identified on the disk by suitablemarkings readily to inform the observer of such ranges and it will beunderstood that additional radials may subdivide the interveningsectors, or the disk may carry in the latter graduations, for moreaccurate information as to range and also to permit such a rotary diskto be used as a range finder if desired. Such a disk will beparticularly designed for .each type of weapon on which it is to bemounted as the front sight thereof with respect to the particularammunition that has been standardized for use therein.

The bracket strip also has its rear face provided with a suitableguidance marker or pointer, such as a scribed vertical line (VH), andinitially in designing the disk 33 for use on a particular weapon, suchas an LAW having an effective range of about five hundred (500 meterswith the ammunition specially designed for use therein, the pivotallymounted disk will be rotated to align its one hundred (100 meter radial(RR-l) with the pointer line (VH). The weapon will then be raised to thefiring position on a testrange of known characteristics and under suchconditions that the line of sight through the (RS) peephole and a lowersector of the (FS) disk 33 is level. This will determine the location ofa point (KP-l) to be marked on the radial (RR-l) which represents thekill or hit point, i.e., the point of ing radials (RR-2, RR-3, RR-4, andRR-S) to define thereon the series of successive points (KP-1, KP-Z,KP-3, KP-4, and KP-S), with the same target being located respectivelyat the proper ranges for each of these radials. These hit points willthus have defined on the rear face of this disk a series thereof whichspirals gradually outward toward the periphery of the latter and theywill guide the scribing thereon of a spiraling curved line (AEL-angularelevation line) which will indicate at these range distances andintermediate range distances the desired point of impact on the intendedtarget at such ranges.

The rear face of this front sight disk 33 will then be provided withsuitable curved spiraling marginal lines for framing the height of theimages of the target at the various ranges. These marginal stadia(FSB-framing stadia bottom) and (FST-framing stadia top) are scribed onthe rear face of the front sight disk 33 in accordance with adetermination of the width of such framing area at the various ranges,and this spacing (Ws may be determined at any particular range by thefollowing equation:

(Ws= Bh/R), in which Ws is spacing between marginal lines for framingthe object height at the top and bottom of target mock-up; B is distancefrom front sight to rear sight;

h is height of target; and R is distance to target from rear sight.

By way of example, it may be assumed that a target mock-up for thepurpose of this equation and the laying out on the sight disk 33 of thespiraling marginal stadia (PS8) and (FST) may have a height (h) of tenfeet (120 inch or 3.048m). Assuming that the distance (B) from the rearsight peephole (RS) and the front sight (FS) is one-half meter (0.5m or19.7 inch) the spacing (Ws) between the marginal stadia (FSB) and (FST)at the various range radials (RR) is computed in the following manner;

These calculations may be tabulated as follows:

Range m It will thus be seen that the spiraled area defined between themarginal stadia (F88) and (FST) gradually recedes from the central diskaxis 32 toward the periphery of the disk with these stadia graduallyconverging, so that the radial distance from the disk axis to a selectedportion, such as the desired point of impact, of the target image thatis framed in this area is indicated by the curved medial line (AEL) asthe angular elevation necessary to accommodate the characteristictrajectory of a certain projectile at the target range which isindicated by the length of the radial of this disk to such impact point.Since the angular location on the disk 33 of any particular radiusthereof (marked or not thereon) identifies a certain range between thepoint of observation and the location of the distant object, the closeframing of an image of the latter between the marginal stadia (FSB) and(PST) at a point of reference, such as the vertical hairline (VH) ofFIG. 4, so that the radius which is aligned with the latter extendsapproximately through the center of such image, this angular position ofthe disk or location of this radius can be read as the range. At thissame time the radial distance along this disk radius between the diskaxis and the approximate center of the distant object, such as wherethis radius crosses the angular elevation line (AEL) that willconstitute the kill point or point of impact (KP), indicates the angularelevation necessary to accommodate the characteristic trajectory of acertain projectile.

In the FIG. diagrammatic view is indicated the sighting system of thegun of FIG. 1, employing the rear sight (RS) of FIG. 2 and the frontsight (FS) of FIG. 4, with a target (X) located at a range distance(R-2), of 200m) from the point of observation or the location of therear sight and, alternatively, located at'a range distance (R-5) of(500m) from that point of observation. It will be seen that the height(h) of the target at (X-2) subtends a relatively wide angle which, atthe vertical plane of the front sight (FS), is also subtended by theframing area width (Ws-2). It will also be seen that the height (h) ofthe target at (X-S) subtends a relatively smaller angle which at thevertical plane of the front sight (FS) is also subtended by therelatively smaller framing area width Ws-5).

It will be noted from FIG. 5 that the trajectory (Th-2) of therelatively flat trajectory path (TP-2) at the range (200m) requires arelatively small angular elevation of the axis of the gun tube 1 l inorder that the projectile shall hit the target (X-Z) at the kill point(KP-2). This is more graphically illustrated in FIG. 6 wherein-therelatively small angle of elevation is indicated at (01-2). It willfurther be seen that the trajectory Th-S) of the more highly archedtrajectory path (TP-S) requires a relatively larger angular elevation ofthe axis of the gun tube 11 in order that the projectile shall hit thetarget (X-S) at the kill point (KP-5). This latter is more graphicallyillustrated in FIG. 7'wherein the relatively larger angle of elevationis indicated at (a-S). a a.

It is to be understood that while it is preferred to form the rotarydisk 33 from see-through or transous that in producing such a range andelevation determining device in the manner indicated it may be preparedfor variously differing types of targets each having its own average orstandardized height, so that a weapon equipped therewith may beaccurately used against differing targets, e.g., pillboxes, troops,fortifications, and other types of vehicles. Such a range and elevationdetermining disk may also be utilized as a reticule in opticalinstruments, such as binouculars, gunners telescopes and periscopes, toprovide accurate range and elevation data for use by gunners. For

the latter purpose the rear face of the disk may bear' readablegraduated scales with one arranged in an annular zone of the disk toindicate range and one or more others provided radially thereof toindicate angu lar elevation.

The designation herein of a range and elevation determining device isnot used in a sense to imply that the device itself must bear indicia ormarkings which permit direct reading of such values. In certain forms ofthese devices which embody the features of the invention the shapes andsizes of structural parts, when produced or assembled in accordance withthe teachings herein, either automatically impose such values upon thedesired and attained end result without requiring a direct readingthereof or give information from which such values may be translated, ifdesired.

It will thus be seen that the objects set forth above, among those madeapparent from the preceding description, are efficiently attained and,since certain changes may be made in the above constructions withoutdeparting from the scope of the invention, it is intended that allmatter contained in the above description or shown in the accompanyingdrawings shall be interpreted as illustrative and not in a limitingsense.

Having described our invention, what we claim as new and desire tosecure by Letters Patent is the novel subjects matter defined in thefollowing claims.

We claim:

1. A range and elevation determining device comprising a rotatablymountable disk provided with a spiraled see-through framing area definedbetween curved marginal framing stadia that gradually converge in theintended direction of disk rotation for closely framing visuallytherebetween the image height of a distant object, said framing area atits greatest width being located most closely to the axis of rotation ofsaid disk and spiraling gradually outward toward the .periphery of thelatter as its marginal stadia progressively converge whereby uponclosely framing such object image height between said stadia at anyparticular radial location the latter and the radial distance from theaxis of said disk to a selectedportion of the framed parent plasticsheet it may be formed of opaque sheetto form a spiraled slot with thecurved edges thereof constituting its marginal stadia. Also, it shouldbe obviindicating at least some of the radial locations at which i suchobject image framing is to be effected.

3. The range and elevation determining device of claim 1 in which thespiraled framing area is in the form of a spiraled slot with the curvededges thereof constituting its marginal stadia.

4. The range and elevation determining device of claim I in which saiddisk is in the form of a seethrough sheet with the spiraled framing areadefined thereon by curved lines to constitute the marginal framingstadia.

5. The range and elevation determining device of claim 4 in which thespiraled framing area is provided with a longitudinally extending,curved medial line scribed through desired points of impact at variousranges for a certain type of object that is to be an intended target.

6. The range and elevation determining device of claim 2 in which saiddisk is rotatably mounted in an upright plane on the muzzle of aprojectile shooting in which (Ws) is the spacing between the curvedmarginal stadia for framing the height of an image of a particular knownobject as the intended target, (b) is the distance nths s f ta PWEQLQQ), is 19 10 probable height of the target object and (R) is the rangedistance between the rear sight and the target object.

7. The frontweapon sight of claim 6 in which said disk is in the form ofa see-through sheet with the spiraled framing area defined thereon bycurved lines to constitute the marginal framing stadia between which isscribed a curved medial line extending through points at the rangedistances radii which indicate at these range distances thepredetermined point of vulnerability of the intended target with thismedial line defining the hit point at each of all the range distancesbetween the initial and terminal points of this curved framing area andwith the radial distance between this hit point line and the axis ofsaid disk indicating the angular elevation of the weapon tube relativeto the line of sight.

8. The front weapon sight of claim 7 in which the circumferential rim ofsaid disk is exposed for engagement by a gunners hand for rotationthereof about its axis to attain close framing of the target imageheight in the curved framing area by the marginal stadia of the latterat the actual range distance.

1. A range and elevation determining device comprising a rotatablymountable disk provided with a spiraled see-through framing area definedbetween curved marginal framing stadia that gradually converge in theintended direction of disk rotation for closely framing visuallytherebetween the image height of a distant object, said framing area atits greatest width being located most closely to the axis of rotation ofsaid disk and spiraling gradually outward toward the periphery of thelatter as its marginal stadia progressively converge whereby uponclosely framing such object image height between said stadia at anyparticular radial location the latter and the radial distance from theaxis of said disk to a selected portion of the framed image indicatesthe range between the location of the object and that of observation andthe angular elevation necessary to accommodate the characteristictrajectory of a certain projectile.
 2. The range and elevationdetermining device of claim 1 in which radii of said disk are delineatedthereon as representative of certain range distances for indicating atleast some of the radial locations at which such object image framing isto be effected.
 3. The range and elevation determining device of claim 1in which the spiraled framing area is in the form of a spiraled slotwith the curved edges thereof constituting its marginal stadia.
 4. Therange and elevation determining device of claim 1 in which said disk isin the form of a see-through sheet with the spiraled framing areadefined thereon by curved lines to constitute the marginal framingstadia.
 5. The range and elevation determining device of claim 4 inwhich the spiraled framing area is provided with a longitudinallyextending, curved medial line scribed through desired points of impactat various ranges for a certain type of object that is to be an intendedtarget.
 6. The range and elevation determining device of claim 2 inwhich said disk is rotatably mounted in an upright plane on the muzzleof a projectile shooting weapon as its front sight and which isobservable through a rear sight of the latter, the transverse width (Ws)of the spiraled framing area at any point along the latter beingdeterminable be the formula (Ws Bh/R), in which (Ws) is the spacingbetween the curved marginal stadia for framing the height of an image ofa particular known object as the intended target, (b) is the distancebetween these front and rear sights, (h) is the probable height of thetarget object and (R) is the range distance between the rear sight andthe target object.
 7. The front weapon sight of claim 6 in which saiddisk is in the form of a see-through sheet with the spiraled framingarea defined thereon by curved lines to constitute the marginal framingstadia between which is scribed a curved medial line extending throughpoints at the range distances radii which indicate at these rangedistances the predetermined point of vulnerability of the intendedtarget with this medial line defining the hit point at each of all therange distances between the initial and terminal points of this curvedframing area and with the radial distance between this hit point lineand the axis of said disk indicating the angular elevation of the weapontube relative to the line of sight.
 8. The front weapon sight of claim 7in which the circumferential rim of said disk is exposed for engagementby a gunner''s hand for rotation thereof about its axis to attain closeframing of the target image height in the curved framing area by themarginal stadia of the latter at the actual range distance.